A. Field of the Invention
The present invention relates to the field of the "sterilization" of biological media or fluids such as blood and blood fractions (e.g., blood plasma, blood serum, blood factor VIII, etc ), genetically engineered protein products and vaccine preparations. The term "sterilization," as applied to the present invention, refers to the deliberate alteration, by photolysis, of the chemical structure of nucleic acid entities in the presence of proteins to cause a loss of viability or infectivity of said entities, while substantially maintaining the functionality of those proteins that are also present. An object of this invention is thus to destroy a significant amount or substantially all DNA and RNA based agents, both known and unknown, including infectious nucleic acid molecules capable of transformation, viroids, and viruses or bacteria which are suspected to be in said media, while leaving the proteins in said media to a large degree or substantially completely intact. Until the present invention, it has not been possible to selectively and efficiently photolyze nucleic acids in the presence, and to the substantial exclusion, of proteins. While the process of this invention can be applied to a wide variety of biological media, three illustrative examples are discussed below.
(Blood Sterilization)
Although various techniques have been proposed for sterilizing blood and blood fractions, at the present time such blood and blood fractions are not effectively sterilized prior to transfusion. As a result, a significant percentage of transfusion recipients contract diseases such as hepatitis, and AIDS, from such transfusions. See New England Journal of Medicine, Vol. 310, pp. 69-75 (1984).
Techniques which have been suggested, but not widely adopted, include passing blood products through bacterial and/or viral filters, adding antibiotics to such products, etc. These have not proven reliable or efficacious (filters are difficult to maintain with sufficient flow; adding potentially toxic agents is undesirable).
It is current practice to test transfusates to identify those which contain certain pathogens. However, such tests are not 100% accurate and there are many pathogens for which there is no known test, and such tests may be time-consuming and expensive.